Dam.



No. 840,110. PATENTED AN l, 190v.

L. OOBURN.

DAM.

APPLICATION FILED MAY 2, 1906.

' mmwwmx HOWARD GOBURN, OF BOESTON. MASSACHUSEFFS.

Bpecification of Letters Patent.

Patented Jan. 1, 1907.

Application filed May 2,1906. Serial No. 314,846.

To altl whom it may candor-us Be it'known that I, IIOWARD L. Concert,

of Boston, in the county of Suffolk and State.

of Massachusetts, have invented certain-new and useful Improvements inDams. of which the following is a specification.

This invention relates to a damiormed to inclose or rotect a spacebetween the up stream and downstream sides of the' dam,

said space being utilized as a power-station by installing thereinower-utih'zing means, such as a turbine an its accessories, a conduitbeing em loyed to supply water'to the turbine from t re upstream side ofthe dam.

The invention is an improvement on a dam of this character in which thesaid conduit discharges the tail-water from the turbine in the lowerortion ot' the space protected by the dam, t re tail-w ater whichaccumulates in the said space flowing therefrom through an outlet underthe overfall passing over the dam. The flow of tail-water from theprotected s ace is accelerated by the action of the over all, whichinduces an outward movement of'the accumulation of tail-water.

My invention has for its object to enable the flow inducing orexhausting function of the overfall to be exerted directly upon thewater at the discharge end of the conduit instead of being exerted on anaccumulation of tail-water discharged within the space protected by thedam.

My invention is therefore embodied in a power-s ace-inclosing dam havinga continu ous con uit extending downwardly from the upstream side of thedarn through the protected space to the downstream side, the outlet endof the, conduit being under the path of the overfall and exposed to theinducing or exhausting action of the latter, so that the flow of waterthroughout the entire length of the conduit, and especially through thedelivering or draft-tube portion thereof, is continuously accelerated, apartial vacuum being constantly maintained at the outlet end .of thedraft-tube. .This vacuum has the same effect that would be produced byan increase of the head of the acting water, the energy of the latterbeing increased and the increase being proportionedto the velocity ofthe flow of the overfall.

Of the accompanying drawings, forming a part of this specification,Figure 1 represents a transverse sectionof a dam embodying my invention.Fig. 2 represents a section on line 2 2 of Fig. 1.

l The same numerals of reference indicate the same parts in both fiures. I i

In the embodiment o my invention here shown for purposes ofillustrationthe dam. is of shell form and of reinforced concrete cor: struction, Itcomprises a deck 12, an apron .13, and a crest -14, uniting the deck andthe upstream and downstream sides of the dam. in said space may heinstalled a turbinc, the casing of which is shown at 15, the shaft 16 ofthe turbine being connected with adynamo or other power-utilizing means.

18 represents a fecd-pi )c, the intake end of which is in the deck 12,the said pipe extending downwardly to the wheel-casing.

11) represents a drafutube, which extends continuously from thewheel-casing to an outlct-opening 2G in the downstream-wall of the dam.and draitdubc 19 thereforeconstitute a continuous conduit cxteiulingdownwardly from the upstream side of the dam through the space protectedby the dam to the downstream side and discharging outside the said spaceinstead of discluu'ging, into the lower portion of the space, thedrafttube having a liquid-tight connection with the lower portion of theapron 13, so that the discluugo from the draft-tube is wholly externalto the space protected by the dam.

the overiall, the portion of the apron. over the outlet being soinclined that the overfall is projected forcibly downstream from thedelivering end of the outlet. of the overlull creates a partial vacuumat the outlet 20, and therefore exhausts water and air directly from thedraft-tube 19. The llow of water through the entire conduit, andespecially through the draft-tube portion thereof, is thus materially:accelerated, the degree of,acceleration depending on the velocity of theovcri'ull' at the mint where it leaves the apronof thedam. eexhaustingaction of the oveii'all is concentrated at the draft tubc by theliquid-tight connection of th latter with the downsireany side of thedam and, as already stated, has an cil'ect which is equivalent to anincrease in the head of the w ter flowing through the conduit. It willbe seen, therefore, that by extending the draft-tube to the downstreamside of the tothe influence of the, overfall, 'I have ac comphshed adistinctly new resultnamel The feed-pipe .l b, wheel-casing 15 asheretofore,

apron, (the whole covering a space between "the outlet it! is locatedunder the path of dam, so that its discharging end is subjected toincrease the effective head or pressure of the Water. The draft-tube 19is preferably horizontally widened or flared -outwardly gowerd itsdischarging end, as indicated in A i0. 2.

1 claim- A power--spece-inclosing dam' having a continuous conduitextending downwardl from the upstream side of the dam, throu said space,to the downstream side of t e dam, said conduit including a wheel-casingand a draft-tube, the outlet end of the draft tube portion of theconduit being under the path of the overfall, whereby the overfalljiscaused to accelerate the flow of water through the draft-tube.

In testimony whereof I have affixed my signature in presence oftwoWitnesses.

HOWARD L. COBURN. Witnesses:

C. F.-BROW'N, E. BATCHELDER

